Hi, The QMidiArp plugins work with jalv.gtk and ardour4 on my system, both using suil's libsuil_qt5_in_gtk2.so , which on my distro is installed in /usr/lib64/suil-0. But I don't have ardour5. Could you try jalv.gtk https://git.code.sf.net/p/qmidiarp/lfo in a terminal and see whether this works? I understand the mess with different toolkit library versions and LV2, but qmidiarp as an application has been using Qt ever since, so the module GUIs are also Qt. Regarding carla there seem to be communication...

Hi Wayne, you actually found a new bug ! It hasn't anything to do with this one, but thank you for the nice analysis that helped me solving it. The vel 1 notes should actually just not be there, this was an annoying regression. Should be fixed in the last commit I just did.